Ask Max: Are Leopard Processor requirements firm
The system requirements for processor speed for Leopard are stated by Apple to be 867 MHz or faster G4 or better.Will Leopard not load on my 450 MHz G4, or will Leopard simply run at less that optimum speeds?I am currently operating very comfortably with OS 10.4.10, 1.75 GB RAM, and 440 GB total internal hard drive storage.I can't find anything on the Mac OSX website to answer this.
The short answer is "no," you have to have a G4 867 GHz processor or higher Mac to install Leopard. However, I don't like the "short answers," so I've been playing the Mac OS Limbo: "How low can you go?"The result of my Caribbean Mac dance was that anything with a G3 chip in it fell flat on its back; you will have to have a G4 chip. I have tested it on most generations of G4 PowerBooks and Power Macs. In nearly all the attempts, a Leopard drive will boot up G4 Macs, 400MHz or higher.So you may be asking why the short answer was "no." Just because the Leopard OS works on all G4s, it does not mean that it will work well on all G4 Macs. Apple didn't want to give anyone the possibility of having a bad Leopard experience. So Apple blocked the install DVD from running the installer on a computer under the 867 MHz cut-off. The solution is to run the installer from a PowerPC G4 that does meet the basic requirements of the Leopard installer, but set the destination to be the hard drive of your unsupported Mac. Boot your destination (sub 867MHz) Mac in Target disk mode by holding down the "T" key on startup. Now connect the destination computer to your installer Mac (PowerPC G4 867MHZ or higher) with a FireWire cable. Now boot up your installer Mac off the Leopard DVD and start moving through the install screens. When you get to the point of selecting a place to install onto, select the destination Mac's hard drive. It will look like a FireWire hard drive.After the install is done, you can power down everything and remove the FireWire cable. Turn both computers on again and you should have a sub-867MHz G4 Leopard computer. This process only works if you have access to a second PowerPC Mac that Leopard will install onto. Intel Macs will not work for this kind of install. Also your performance will not be great. The best low-end install of Leopard I had was on 533MHz and higher G4 Macs. Be prepared to reinstall Tiger if you hate the performance of Leopard on your sub-867MHz G4 Mac.